A. Field of the Invention
The present invention relates to watercraft, specifically small boats called jet skis that are adapted to hold a single rider and which are powered by a gasoline engine-driven jet pump. More particularly, the invention relates to an improved handle pole construction for jet skis.
B. Description of Background Art
Small personal watercraft adapted to hold a single person and referred to as "jet skis" are becoming increasingly popular. Most jet skis are powered by a gasoline engine-driven pump that provides a rearward directed stream or jet of water to propel the craft. Usually, the output nozzle of the pump is pivotably mounted to the underside of the rear portion of the hull in a manner permitting horizontal motion of the rear opening of the nozzle, thereby allowing the thrust vector of the jet to be pivoted in a desired direction to steer the craft
Jet skis are typically piloted by an operator standing or kneeling on the aft portion of the craft. Usually, a flat, padded platform or tray is provided for the operator to stand or kneel on.
In most jet skis, steering and engine controls are mounted on the aft end of a handle pole that is located ahead of the platform. Typically, the steering control consists of a pair of handlebars that protrude laterally outwards from the aft end of the handle pole. The handlebars are pivotable with respect to the longitudinal axis of the handle pole and are connected to a shaft which is mechanically coupled to the jet nozzle, usually by means of cables.
Most handle poles are pivotably mounted to the forward portion of the hull, in a manner permitting vertical pivotal motion of the aft end of the handle pole on which the handlebars and engine throttle controls are located. Thus, most handle poles are pivotably mounted at the front end of the handle pole to provide vertical pivotability of the handle pole. The reason for providing vertical pivotability for the handle pole of the jet ski is to permit the handlebars to be positioned at various heights above the operator's platform. For example, when the operator is in a kneeling position on the platform the handle pole would typically be pivoted downward to its lowest position. Conversely, with the operator standing on the platform, the handle pole would usually be pivoted upwards to a position intermediate its lower and upper travel limits.
During vigorous operation of a jet ski, especially on rough water, the craft may experience rather substantial pitching, and/or vertical translational motions. During such motions, experienced jet ski operators assume a partially crouched position, using their knee joints as shock absorbers while the handle pole which is gripped by the operator is maintained at a relatively constant height above the platform, by cooperative pivotal action of the arms. While this stance aids the operator in maintaining a firm grip on the handlebars during vigorous maneuvers, supporting the weight of the aft end of the handle pole can tire the arms. For this reason, a variety of mechanisms have been proposed to counterbalance or counteract the downward force exerted by the aft end of the handle pole on the arms of an operator gripping the handlebars. For example, U.S. Pat. No. 4,733,627, Mar. 29, 1988, Nishida discloses a resistance mechanism connected between the control handle and hull of a boat. The resistance mechanism includes an air cylinder having a piston which is biased to a contracted position by means of a helical extension spring within the cylinder. A bypass pipe allows the piston to displace air freely for a fixed stroke length until the piston reaches a port of the bypass pipe, and consequently there is almost no resistance (except that of the spring) when the handle is moved from a horizontal position to a central position at which point the piston closes the port. If the handle is moved further from the central position, air trapped inside the cylinder is compressed as the piston moves, creating a resistance to movement. The handle can be set to a specific position by moving it to that position and manually opening and then reclosing a valve mounted in a second bypass tube connected to opposite end walls of cylinder. A second means for resisting handle pivoting disclosed in Nishida includes a coiled torsion spring wrapped around the handle's pivot shaft and attached to the hull and handle. A third means disclosed in Nishida consists of an elastic section positioned between a stop attached to the hull and a cam formed on the outer surface of the handle.
In U.S. Pat. No. 5,103,754, Apr. 14, 1992, Fujitsubo, a shock absorber for jet ski handles is disclosed which is used with a handle bar biased upwards by a coil spring. The shock absorber, which is mounted externally to the handle, comprises a cylinder-and-piston assembly, the cylinder and piston of which are pivotably attached to a water jet ski body and to the handlebar of the water jet ski respectively. The fluid filled in the cylinder is allowed to pass through the orifices of the piston body while the piston moves back and forward in the cylinder in response to the rise and descent of the handlebar. With this arrangement the rider can move the handlebar up and down freely so as to permit him to keep his balance on the water jet ski while running on water. The orifice size is selected to be appropriate for the purpose of preventing uncontrollable quick move of the handlebar which otherwise would be caused by sudden application of a strong force to the water jet ski body, thereby preventing the rider from losing his balance on the water jet ski.
U.S. Pat. No. 5,113,777, May 19, 1992, Kobayashi, discloses a steering device for jet boats in which an air strut is interposed between the ski assembly and the hull so as to provide controlled movement of the ski vertically relative to the steering shaft. The strut has a pivotal connection to a boss at the forward portion of the ski and a pivotal connection to the upper bracket for the steering shaft.
No prior art devices known to the present inventor, including those discussed above, provide means for limiting the downward force exerted on the arms of a let ski operator by the handle pole, that do not have certain drawbacks. For example, the fluid cylinders in Nishida and Fujitsubo are external to the handle pole. The external location of the cylinders detracts from the aesthetic appearance of the jet skis to which the cylinders are attached. Moreover, the space between the hull, handle and external cylinder provides a possibly dangerous trap for the arms or legs of an operator boarding or unboarding the craft.
In view of perceived limitations of prior art approaches to providing a support mechanism for jet ski handle poles that is both functional and comfortable for the operator to use, the improved handle pole construction according to the present invention was conceived of.